Field of the Disclosure
The present disclosure relates to metallic alloys, and more particularly to the formation of bulk amorphous metal alloys containing metalloid constituents.
Background Information
Bulk metallic glass (BMG) alloys are a family of materials that, when cooled at rates generally less than 100° C./s, form an amorphous (or non-crystalline) microstructure with thicknesses in the range of 0.1 to 10 mm or greater. BMGs may have unique and novel properties given their lack of long-range order and absence of crystalline structure. BMG alloys may have exceptional strength, high elasticity, limited plasticity, good corrosion and wear resistance, and high hardness relative to their crystalline counterparts. From a processing perspective, the alloys also offer unique possibilities. BMG alloys may have melting temperatures far below their constituent elements, allowing for permanent mold casting processes and other processing such as thermoplastic forming, which are not possible with many conventional alloy systems.
Some good glass forming alloys contain metalloids such as phosphorus (P). While P is often considered a non-metal, it may exhibit borderline metalloid behavior such that it may also be considered a metalloid. Other metalloid elements include boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te). For example, BMG alloys based on Pt, Pd, Ni, Co, Fe, and/or other elements that contain significant quantities of P may have critical cooling rates as low as 1° C./s or less. Examples of such alloys are described in U.S. Pat. Nos. 7,896,982, 8,066,827, 7,582,172, 7,540,929, 6,749,698, 8,361,250 and U.S. Patent Application Publication Nos. 20120168037, 20120168036, 20100185076 and 20130048152, the entire contents of each of which are incorporated herein by reference.
While such metalloid-containing alloys can be good glass formers and may have desirable properties, the present inventors have observed that their preparation may be cumbersome in view of various challenges presented by the chemistry of such alloys. For instance U.S. Pat. No. 7,540,929 discloses the preparation Pd—Cu—Co—P alloys by placing Pd, Cu, and Co into a quartz tube under an inert atmosphere, e.g., Ar or He, and inductively heating those constituents to produce a pre-alloy of Pd—Cu—Co. P is added to the pre-alloy, the quartz tube is sealed under an inert atmosphere, and heat is added by increasing the temperature intermittently to accommodate the rising gas pressure of the subliming phosphorous.
The present inventors have observed a need for improved approaches of preparing such alloys. Exemplary approaches described herein may address such needs.